分类： 天文学 >> 天文学 提交时间： 2023-02-19
Yuming Wang
Xianyong Bai
Changyong Chen
Linjie Chen
Xin Cheng
Lei Deng
Linhua Deng
Yuanyong Deng
Li Feng
Tingyu Gou
Jingnan Guo
Yang Guo
Xinjun Hao
Jiansen He
Junfeng Hou
Huang Jiangjiang
Zhenghua Huang
Haisheng Ji
Chaowei Jiang
Jie Jiang
摘要： Solar Ring (SOR) is a proposed space science mission to monitor and study the Sun and inner heliosphere from a full 360{\deg} perspective in the ecliptic plane. It will deploy three 120{\deg}-separated spacecraft on the 1-AU orbit. The first spacecraft, S1, locates 30{\deg} upstream of the Earth, the second, S2, 90{\deg} downstream, and the third, S3, completes the configuration. This design with necessary science instruments, e.g., the Doppler-velocity and vector magnetic field imager, wide-angle coronagraph, and in-situ instruments, will allow us to establish many unprecedented capabilities: (1) provide simultaneous Doppler-velocity observations of the whole solar surface to understand the deep interior, (2) provide vector magnetograms of the whole photosphere - the inner boundary of the solar atmosphere and heliosphere, (3) provide the information of the whole lifetime evolution of solar featured structures, and (4) provide the whole view of solar transients and space weather in the inner heliosphere. With these capabilities, Solar Ring mission aims to address outstanding questions about the origin of solar cycle, the origin of solar eruptions and the origin of extreme space weather events. The successful accomplishment of the mission will construct a panorama of the Sun and inner-heliosphere, and therefore advance our understanding of the star and the space environment that holds our life.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Youqian Qi
Zhenghua Huang
Lidong Xia
Hui Fu
Mingzhe Guo
Zhenyong Hou
Weixin Liu
Mingzhe Sun
Dayang Liu
摘要： Dynamic features, such as chromospheric jets, transition region network jets, coronal plumes and coronal jets, are abundant in the network regions of the solar polar coronal holes. We investigate the relationship between chromospheric jets and coronal activities (e.g., coronal plumes and jets).We analyze observations of a polar coronal hole including the filtergrams that were taken by the New Vacuum Solar Telescope (NVST) at the H{\alpha}-0.6 {\AA}to study the H{\alpha} jets,and the Atmospheric Imaging Assembly (AIA) 171 {\AA} images to follow the evolution of coronal activities. H{\alpha} jets are persistent in the network regions, only some regions (denoted as R1-R5) are rooted with discernible coronal plumes.With an automated method, we identify and track 1 320 H{\alpha} jets in the network regions. We find that the average lifetime, height and ascending speed of the H{\alpha} jets are 75.38 s, 2.67 Mm, 65.60 km s$^{-1}$, respectively. The H{\alpha} jets rooted in R1-R5 are higher and faster than those in the others. We also find that propagating disturbances (PDs) in coronal plumes have a close connection with the H{\alpha} jets. The speeds of 28 out of 29 H{\alpha} jets associated with PDs are about 50 km s$^{-1}$ . In a case of coronal jet, we find that the speeds of both the coronal jet and the H{\alpha} jet are over 150 km s$^{-1}$, suggesting that both cool and hot jets can be coupled together. Based on our analyses, it is evident that more dynamic H{\alpha} jets could release the energies to the corona, which might be the results of the development of Kelvin-Helmholtz instability (KHi) or small-scaled magnetic activities. We suggest that chromospheric jets, transition region network jets and ray-like features in the corona are coherent phenomena, and they are important tunnels for cycling energy and mass in the solar atmosphere.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Coronal upflows at the edges of active regions (AR), which are a possible source of slow solar wind, have been found to connect with dynamics in the transition region. To infer at what scale transition region dynamics connect to AR upflows, we investigate the statistical properties of the small-scale dynamics in the transition region underneath the upflows at the edge of AR NOAA 11934. With observations from the Interface Region Imaging Spectragraph (IRIS), we found that the Si IV 1403\,\AA\ Doppler map consists of numerous blue-shifted and red-shifted patches mostly with sizes less than 1\,$Mm^2$. The blue-shifted structures in the transition region tend to be brighter than the red-shifted ones, but their nonthermal velocities have no significant difference. With the SWAMIS feature tracking procedure, in IRIS slit-jaw 1400\,\AA\ images we found that dynamic bright dots with an average size of about 0.3\,$Mm^2$ and lifetimes mostly less than 200\,s spread all over the region. Most of the bright dots appear to be localised, without clear signature of propagation of plasma to a long distance on the projection plane. Surge-like motions with speeds about 15 km/s could be seen in some events at the boundaries of the upflow region, where the magnetic field appear to be inclined. We conclude that the transition region dynamics connecting to coronal upflows should occur in very fine scale, suggesting that the corresponding coronal upflows should also be highly-structured. It is also plausible that the transition region dynamics might just act as stimulation at the coronal base that then drives the upflows in the corona.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Yuming Wang
Xianyong Bai
Changyong Chen
Linjie Chen
Xin Cheng
Lei Deng
Linhua Deng
Yuanyong Deng
Li Feng
Tingyu Gou
Jingnan Guo
Yang Guo
Xinjun Hao
Jiansen He
Junfeng Hou
Huang Jiangjiang
Zhenghua Huang
Haisheng Ji
Chaowei Jiang
Jie Jiang
摘要： Solar Ring (SOR) is a proposed space science mission to monitor and study the Sun and inner heliosphere from a full 360{\deg} perspective in the ecliptic plane. It will deploy three 120{\deg}-separated spacecraft on the 1-AU orbit. The first spacecraft, S1, locates 30{\deg} upstream of the Earth, the second, S2, 90{\deg} downstream, and the third, S3, completes the configuration. This design with necessary science instruments, e.g., the Doppler-velocity and vector magnetic field imager, wide-angle coronagraph, and in-situ instruments, will allow us to establish many unprecedented capabilities: (1) provide simultaneous Doppler-velocity observations of the whole solar surface to understand the deep interior, (2) provide vector magnetograms of the whole photosphere - the inner boundary of the solar atmosphere and heliosphere, (3) provide the information of the whole lifetime evolution of solar featured structures, and (4) provide the whole view of solar transients and space weather in the inner heliosphere. With these capabilities, Solar Ring mission aims to address outstanding questions about the origin of solar cycle, the origin of solar eruptions and the origin of extreme space weather events. The successful accomplishment of the mission will construct a panorama of the Sun and inner-heliosphere, and therefore advance our understanding of the star and the space environment that holds our life.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Zhenyong Hou
Hui Tian
Hechao Chen
Xiaoshuai Zhu
Zhenghua Huang
Xianyong Bai
Jiansen He
Yongliang Song
Lidong Xia
摘要： Coronal loops are building blocks of solar active regions. However, their formation mechanism is still not well understood. Here we present direct observational evidence for the formation of coronal loops through magnetic reconnection as new magnetic fluxes emerge into the solar atmosphere. Extreme-ultraviolet observations of the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) clearly show the newly formed loops following magnetic reconnection within a plasma sheet. Formation of the loops is also seen in the h{\alpha} line-core images taken by the New Vacuum Solar Telescope. Observations from the Helioseismic and Magnetic Imager onboard SDO show that a positive-polarity flux concentration moves towards a negative-polarity one with a speed of ~0.4 km/s, before the formation of coronal loops. During the loop formation process, we found signatures of flux cancellation and subsequent enhancement of the transverse field between the two polarities. The three-dimensional magnetic field structure reconstructed through a magnetohydrostatic model shows field lines consistent with the loops in AIA images. Numerous bright blobs with an average width of 1.37 Mm appear intermittently in the plasma sheet and move upward with a projected velocity of ~114 km/s. The temperature, emission measure and density of these blobs are about 3 MK, 2.0x10^(28) cm^(-5) and 1.2x10^(10) cm^(-3), respectively. A power spectral analysis of these blobs indicates that the observed reconnection is likely not dominated by a turbulent process. We have also identified flows with a velocity of 20 to 50 km/s towards the footpoints of the newly formed coronal loops.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： Jets are one of the most common eruptive events in the solar atmosphere, and they are believed to be important in the context of coronal heating and solar wind acceleration. We present an observational study on a sequence of jets with the data acquired with the Solar Dynamics Observatory (SDO) and the Interface Region Imaging Spectrograph (IRIS). This sequence is peculiar in that an EUV jet, $\sim29\arcsec$ long and with a dome-like base, appears to be a consequence of a series of transition region (TR) micro-jets that are a few arcsecs in length.We find that the occurrence of any TR micro-jets is always associated with the change of geometry of micro-loops at the footpoints of the microjets. A bundle of TR flux ropes is seen to link a TR micro-jet to the dome-like structure at the base of the EUV jet. This bundle rises as a response to the TR micro-jets, with the rising motion eventually triggering the EUV jet. We propose a scenario involving a set of magnetic reconnections, in which the series of TR micro-jets are associated with the processes to remove the constraints to the TR flux ropes and thus allow them to rise and trigger the EUV jet. Our study demonstrates that small-scale dynamics in the lower solar atmosphere are crucial in understanding the energy and mass connection between the corona and the solar lower atmosphere, even though many of them might not pump mass and energy to the corona directly.
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